This component proposes to investigate perseverative behavior in fluent and nonfluent aphasic stroke patients, Parkinson's disease patients with and without dementia, and Alzheimer's disease patients. Descriptive aims include the documentation of frequency and nature of perseveration in its stuck-in-set, continuous, recurrent, and ideational forms. Theoretical aims include the study of the relationship of memory functions to the frequency and nature of perseveration management techniques for reducing the behavior. The proposed investigation will provide valuable information about the similarities and differences in perseveration patterns of patients with the various neurologic disorders mentioned. Further, the investigation promises to provide an empirical base from which to develop compensations for this pervasive problem that seriously impedes communication.